Elevating truck with safety lock



D. E. HENNESSY 1,827,012

ELEVATINQ TRUCK WITH. SAFETY LOCK 7 Oct. 13, 1931.

F led July 23, 1929 Dome] Hennessy bywmkw AITys.

. PATENTQFFICE DANIEL HENNESSY,- on msm'owm MA'ssAoiIUsETTs, Assrenon To WIS- SHEPARD COMPANY, oHUsE -Ts ELEVATING TRUCK I Application filed 'Ju1y;2 3,

This invention relates to improvements in elevating trucks and; the-principal Object thereof is to provlde safety mechanism for preventing injury to 'thefloper'ator by reason of alfflying lifting lever or'tongu'e.

The invention more particularly relates to improvements in elevating trucks in which the load supporting means is raised step by step by mechanism operated by a downward swinging movement'of the tongue to lift the invention will more fully appear from/thefollowing description and the accompanying drawings and will be particularlypointed out inthe'claims; j A preferred embodiment of the invention lead supporting means.

Where, during thelifting of the .load'supporting means, or when the load supporting f means of an elevatingtruck is in raised position, the means for locking the same fails to engage or becomes disengaged, the descent of the load supporting means, particularly when heavily loaded, will cause the tongue to fly upwardly with great foreeand-in some instances hasseriously injured the operator of the truck. By the prese'ntinventio'na safety device is provided which will prevent the release of the looking-mechanism while the tongue is so co-ordinated with the lifting means that the descent of the load supporting means will cause the lifting lever or tongue to fiy upwardly.

A further object of the invention is to 'provide a safety -'devi'ce of the character above described which will not interfere with the proper steering. of the truck.

A further object of the invention is to provide simple safety means of the-character above, specified of a rigid character and so constructed as alwaysto be dependable.

These and other objects and featureso'f the is illustrated in the accompanying drawings as applied to an elevating truck operable to raise the load supporting means stepby. step.

of the typeillustrated in Patent No. 1,445;-

838 granted to Lewis Shepard Company as-. signee of Ralph M. L'ovejoy February 205' 1923, and in viewv of the disclosure in such patent only so much ofthe truckis illus-- trated in the accompanying drawings as is OF WATER'IOWN, MASSACHUSETTS, A CORPORATION OI IIIASSA- WITH SAFETY Loox 1929. semi N. 380,294.

required to show the application of the pres ent invention thereto... In the drawings: p Fig. 1 is a perspective viewof the front "portion of an elevating truck of the type described having a detent forpreventing depression of the pedal which releasesthe lo'cking dog, the tongue beingshown in elevated position and the 'detent swung to inoperative position to permit actuation of the pedal; Fig. 2 is a similar view illustrating the detent in normal position to preventd'epression ofthe pedal which releases the locking mechanism and showing the tongue in substantially horizontal steeringposition; v 3 is a detail view showing the pedal arm in cross section and illustratingin full' lines the detent in inoperative position and in dotted lines the detent'in operativep'o'sitionto prevent depression of the pedal; and

, Fig. tis adetailwiew illustraing themechanism for controlling and actuating'the looking dog which retains the load support supported main frame having side bars Icon" V n'ected at their forward ends by an arched head 2 having a central integral steering" head 3 inwhich is'mountedthe steering post of the steering mechanism.

ing yoke 4 having atits ends bosses for-the" 326.65 of the front wheel or wheels 6. The upperend of thesteering postf has scuredto it a split collar 7 provided with upwardly i p v I The steering post is'pr'ovided with a downwardly extend 1 eXtend'ingearsS having, bosses which receive a short shaft?) upon which the metallio base] 10' of a steering/tongue 11 is pivotally mounted. I v v I Y he base 10 0f the ste'ering'tongue" ispr'os vided with a rearward bifurcated xtension- 12 having a transverseipivot 13 upon which a strut H'isso' mounted that; upon vertical swinging movement of the tongue the strut; will be" moved lengthwise substantially in, the direction of the axis ofithe' steering post. The upper end of the strut 14 is connected byafluniversal joint 15 to a swivel16 which is rotatably mounted in the end of a pawlactuat' g lever 17 operable, in the manner hereinafter to be described, to raise the load supporting means.

The load supporting means desirably is in the form of a skeleton platform having side bars 18 connected at their front ends to a substantially vertical standard 19 having at its upper end a transverse shaft 20 upon which the lever 17 is mounted.

The load supporting means may be and desirably are supported upon mechanism similar to that illustrated in the Lovejoy patout above mentioned in which a lever, underlying the front end of the load supporting means, is connected to a lifting link 21 which when raised substantially vertically raises the cut end of the platform, with means operable by such supporting lever to raise the rear end of the platform.

The upper end of the lifting link 21 is pivotally connected to a sector-shaped lever which is fulcrumed upon the shaft 20 and is provided at its free end with a series of ratchet teeth 23 adapted to be engaged by a pawl 24 which is rigidly connected to a shaft.

25 mounted in the lever 17 and provided with a handle 26. The pawl mechanism is so constructed that when the handle 26 is in the position illustrated the pawl 24; is held in engagement with the ratchet 23 and a vertical downward swinging movement of the tongue will consequently raise the lever 17 thereby rotating the sector about the shaft 20 and acting through the link 21 will raise the load supporting means one step.

Means are provided for locking the load supporting means against descent at each elevation. Upward swinging movement of the tongue will permit the lever 17 to descend so that the pawl will ride down over the ratchet to engage the next lowest tooth upon the same. Another downward movement of the swinging tongue will again raise the lever 17 as aforesaid to elevate the platform another step, where it will again be held by the locking mechanism. By repeating the operation above described the load supporting means may be raised to its maximum elevation.

The locking mechanism for retaining the load supporting means at each step of elevation comprises a ratchet 27 which is fixedly secured to the lifting link 21 and a co-operating dog 28 which is pivotally mounted upon a shaft extending across the upper end portions of a pair of arms 29 which are pivoted at their lower ends upon a transverse girder of the main frame, which is not shown but which is fully disclosed in the patent to Lovejoy abovementioned. The locking dog 28 is normally held in engagement with the ratchet by a toggle or cam a member of which is rigidly fixed to a shaft 30 having an arm 31 provided with an outwardly extending stud 32 which extends into a slot in the upper end of a link 33 the lower end of which is pivotally connected to an arm 3400 of a pedal 34 which is mounted upon a stud shaft 35 carried by bosses or a bracket upon said cross girder of the frame. A spring 36, which is connected at its lower end to the arm 31 of the shaft .80, and at its upper end to a stud 37 projecting from a downwardly extending web on the lever 17, tends to rock the shaft 30 in a direction to retain the dog 28 in engagement with the teeth of the ratchet 27.

By reason of this construction the dog 28 will engage successively the notches of the ratchet 2? as the load supporting means is raised step by step and prevent the descent of the load supporting means, while the swinging tongue is moved downwardly to permit the pawl 21 to engage another tooth of the ratchet 23 upon the sector 22.

Rapid descent of the load supporting means is prevented by a. vertical dash pot 3 the piston of which is connected at its upper end to a stud 39 projecting from a boss 4:0 upon the lifting link 21, while the lower end of the dash pot is pivotally supported upon the transverse girder of the main frame.

The construction thus described is in all res ects similar to that disclosed in the prior patent to Lo-vejoy above mentioned.

In the particular construction illustrated the means for preventing the release of the locking dog comprises a detent which normally engages the pedal 34 and prevents the depression thereof at all times except when the tongue is raised to a substantially vertical position from which it obviously cannot fiy upwardly to injure the operator if the locking means is released, so that the load supporting means will descend.

As illustrated herein the detent 11 is of arcuate form and is pivotally mounted upon a stud or bolt 4-2 which extends through the arched head of the main frame. The lower end portion of the detent is thickened to provide a counter weight 13 and is provided with a lateral extension which normally underlies the pedal 3 1. The upper end of the detent desirably is provided with a flat abutment 15 of considerable area which lies in proximity to the steering head.

In the construction illustrated the tongue extension 12 has secured to it, preferably by welding, a bracket 46 which is orfset in such a manner that it will not engage the ear 8 of the steering post and a hunter 4L7 is pivotally mounted upon a stud l8 projecting from the bracket in such a manner as to depend therefrom by gravity, and when the tongue is in substantial alinement with the axis of the truck will overlie the abutment of the detent 41. The length of the hunter 47 is such that when the tongue is swung upwardly and approaches substantially vertical position the lower end of the hunter 47 will engage the abutment l5 and when the immi tongue reaches vertical position will sufliciently depress the abutment to swing the lower end of the detent outwardly enough to remove the extension 44 from beneath the pedal 84, thus freeing the pedal so that it may be depressed to release the load suppor ing means. Upon depression ofthe pedal,

therefore, the link 33 acting upon the stud 82 will rotate the shaft 30 of the releasing mechanism and permit or cause the'dog 28 to be disengaged from the teeth of the ratchet 27, thereby permitting the load supporting means to descend. V I

Upon release of the pedal the spring 38 will raise the arm 31 of the rock shaft 30 and acting through the stud 32 will raise the pedal I to normal position, thus permitting the detent to swing inwardly so that the extension at will again engage beneath the pedal and prevent depression thereof.

By reason of the pivotal connection of the hunter 4? to the tongue extension, it will, upon lateral steering movement of the tongue, either pass over theabutment "when the tongue is in substantially lowered position, or when the tongue is in elevated position will be caused to swing aside during the lateral movement of the tongue so that the bunter will in now way interfere with the steering of the truck.

It will be obvious that by reason of this construction the load supporting means will be locked in all positions of elevation in such a manner that it cannotbe released unless the tongue is swung substantially to vertical position where it cannotpossibly fly to injure the operator. I

While a particular embodiment of the invention is disclosed herein as applied to an elevating truck in which theload supporting means is raised step by step, it is obvious that the invention. is equally applicable to elevating trucks in which a single vertical swinging movement of the tongue serves to raise the load supporting means vto its maximum height.

- t is also obvious that the invention broadly disclosed herein may be embodied in different specific forms and may be applied not only to trucks in which the load support-- ing means is raised by a vertical swinging tongue, but also to elevating trucks in which the load supporting means is raised by other forms of vertically swinging lifting levers which will be likely to injure the operator upon release of the load supporting means,

while the lifting lever is in such position that it will be caused to fly upwardly by the descent of the load supporting means.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. An elevating truck comprising load supporting means, means for lifting said load supporting means including a lifting lever mounted 150 Bearing vertically,- releasable 7 means .forlocking said -load supporting means .-in--raised position, andmeans vnorlevertoswing vertically. I

2. An elevating truck compris ng load supporting ymeansf, means for lifting sa1d load supporting fmeans including a lifting lever mounted to swing vertically, means forlock-- ing-said'load supportingmeansin raised posia detent normally engaging said releasing m'eansiand preventing actuation thereof, and

tion,1means for releasing said locking means,

means operable only bythe movement ofsaid- I lifting lever to substantiallyvertical position to disengage sa-ididetent.

f 3. An elevating truck comprising load sup.-

porti ngfmeans, steering mechanism includ ing a tongue mounted to swing vertically,

means operable by a vertical swinging movement of the tongueto raise said loadsupporting means, releasable means for locking the load supportlng means 1n raised position,

' and-means normally..engaging said locking means and acting-t0 preventrelease of said nated Withthe liftingmechanism that the n descent of the loadsupporting means will cause-thetongue to swing upwardly.

4.; An elevating truck comprising load supporting means, steering mechanismineluding a tonguemounted to swing vertically meansoperable by a vertical swinging movementofthe tongue to raise said load supporting means, means for locking the loadsupporting means in raised position, a pedal operable upon depression to release said locking means, and. means for preventing actu ation ofsaid pedal; unless the tongueis in substantially. vertical position.

i5. elevating tr porting means, steering mechanism includin-ga tongue mountedto swing vertically,

means operable by. vertical swinging move ments of;the tonguetoraisesaid load sup porting, means step by step, means for locking said load supporting means at each step'of elevation, im'eans for releasing said locking means, a detent normallyacting. to prevent release of said lockingmeansat any step of only when swung to substantially .vertical position to disengage said detent. v

6. An elevating truck compr sing load sup porting means, steering mechanism including 1? said load supporting means at each step of uck comprising load sup- 7 V elevat on, and means operable by said tongue locking means while the tongue is so co-ordi- 25 e elevation, means for releasing said locking means, compnsmg a pedal, a counterwe1ghted detent having means normally extendingbeneath said pedal to prevent depression thereof, and a member vertically movable by the upward swinging movement of the tongue operable when the tongue is moved substantially to vertlcal position to engage said detent and remove the same from engagement with said pedal.

7. An elevating truck comprising load supporting means, steering mechanism includa tongue mounted to swing vertically, means operable by vertical swinging movements of the tongue to raise said load supporting means step by step, means for looking said load supporting means at each step of elevation, means for releasing said locking means comprising a pedal, a counterfifilgllll'ed 'detent having means normally extending beneath said pedal to prevent depression thereof, and a hunter pivotally mounted upon said tongue and depending therefrom operable when the tongue is moved substantially to vertical position to engage said detent and remove the same from engagement with. said pedal.

8. An elevating truck comprising a frame having an arched head, steering mechanism mounted in said head having a tongue mounted to swing vertically to provide a rearward extension load supporting means, means operable by vertical swinging movements of said tongue extension to raise said load supporting means, means for locking said load supporting means at each step of elevation, means for releasing said locking means comprising a pedal, an arcuate counterweighted detent pivotally mounted upon said head to swing transversely of said frame and provided at its lower end with means normally extending beneath said pedal and at its upper end with an abutment lying in proximity to the steering head of said steering mechanism, and a hunter pivotally mounted upon said tongue extension and depending therefrom operable when the tongue is moved to substantially vertical position to engage said abutment and swing the extension on the lower end thereof from beneath said pedal.

In testimony whereof, I have signed my name to this specification.

DANIEL E. HENNESSY. 

